Antennas and other sensors, such as RF beam scanning arrays used in radar systems, typically utilize a large area antenna array mounted on a rotating platform to revolve the antenna in the azimuth direction. These rotatable platforms allow the array to be oriented at a particular azimuth angle, or to sweep through an entire range of azimuth angles at a predetermined angular rate. In traditional rotating radar systems, one end of the array is pivotally mounted to the rotating platform, forming a cantilevered arrangement in which the array can be tilted to a desired elevation angle by, for example, a hydraulic linear actuator. In this cantilevered configuration, the array often has a center of mass offset vertically and/or horizontally from the center of the rotating platform.
These systems suffer significant drawbacks resulting from their use of traditional rotational motion (i.e. fixing a desired angle of elevation and rotating the array around a single axis) to sweep the array through a range of azimuth angles. Such problems include primary support bearing failures, power limitations and reduced reliability resulting from the use of slip-rings and rotary fluid joints, as well as the need for heavy, complex leveling sub-systems. Further, rotated antenna arrays typically suffer from a cylindrical “dead-zone” generally oriented directly above the rotating array and in which coverage by the scanning antenna array cannot be achieved.
Alternative systems and methods are desired.